With the given code , it will work fine if you use the import lombok.Data; in ProductRequest.
The possibility of 400 Bad Request is may be of your input type mismatch.

• Ensure the field name and types match with Json (price is double, are you giving double value? Look the stack trace)

sample json request body

{
    "name": "Laptop",
    "price": 999.99
}

• Also ensure @Data is from Lombok

Still getting the error please share your log details